nsim: HP-41CV Microcode-Level Simulator

Introduction

nsim is a microcode-level simulator for the HP-41CV programmable scientific
calculator. It is written in C and uses the X window system for display.

The functionality of nsim has been merged into my multi-architecture
calculator simulator Nonpareil.
I consider nsim to be obsolete, and no longer maintain it. It is provided
here for historical interest.

Third party nsim enhancements and ports

There is a
Mac OS X port of nsim
by Maciej Bartosiak. He has significantly improved the appearance, and
his work on the 41C and other models is being incorporated into
Nonpareil.

Christophe Gottheimer has fixed the bank switching and added support for
the HEPAX module to nsim release 0.61. His modified source code is
available on the download page.

Experimental Voyager Support

The HP "Voyager" series of calculators, including the HP-10C, HP-11C, HP-12C,
HP-15C, and HP-15C, used the same "Nut" microprocessor as the HP-41C. I've
begun work on adding Voyager simulation capability to nsim. It is not yet
fully functional, but it does get as far as displaying "Pr Error" then a
cleared X register.

Since it is not yet usable, I haven't packaged a release, but the source code
is in the Subversion repository in branch/voyager.

Note that my newer simulator,
Nonpareil,
includes working Voyager support.

Another nsim

The
Liberouter project
includes an interesing program also called
nsim,
which is a generic compiler, simulator, and debugger for "nanoprocessors"
implemented in FPGAs.